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dye pen

01-11-2013, 05:49 AM

Hey I'm wondering what an acceptable standard is for dye testing welds. Everything I've researched shows that you spray the dye on the weld to check for surface cracks. However is it acceptable or up to aws or asme code to dye the backside of the weld and spray the developer on the weld itself to see if the dye bleeds through the piece?

You spray the dye onto the weld- let sit 10 minutes- wipe off really well then spray the developer on and wait 10-15 minutes and look for the dye to show up on the white developer. Never seen it done the other way though..

Comment

You spray the dye onto the weld- let sit 10 minutes- wipe off really well then spray the developer on and wait 10-15 minutes and look for the dye to show up on the white developer. Never seen it done the other way though..

Clean the weld very well
Apply dye and let penetrate for 15min
Wash off dye with water and rag/towel
Spray on developer and observe. No wait time is necessary here

Because the dye has no surface tension, it gets into tiny spots that the rinsing water can't.

Comment

Hey I'm wondering what an acceptable standard is for dye testing welds. Everything I've researched shows that you spray the dye on the weld to check for surface cracks. However is it acceptable or up to aws or asme code to dye the backside of the weld and spray the developer on the weld itself to see if the dye bleeds through the piece?

No it's not acceptable under those codes. For several reasons.

How in the world would you discover surface cracks by spraying the penetrant on the "back" of the weld? Might as well spray it on the ground a quarter mile away.

Comment

when we check tanks we will spray dye on the inside and developer on the outside (leave for a few hours before checking). this does not meet any codes but will tell you if there is a leak and will hold fluid. this is done buy many companies to check tanks and also worked with some companies that fog dye inside and test the out side to pass for the API certs. so yes this will work to look for leaks in a tank. if you are looking for cracks in the weld zone then use as described on the can.